This invention relates generally to gas turbine engine blade assemblies and, more particularly, to an apparatus for machining blade assemblies.
A gas turbine engine typically includes a core engine having, in serial flow arrangement, a high pressure compressor which compresses airflow entering the engine, a combustor which burns a mixture of fuel and air, and a turbine which includes a plurality of blade assemblies that extract rotational energy from airflow exiting the combustor. Because the turbine is subjected to high temperature airflow exiting the combustor, turbine components are cooled to reduce thermal stresses that may be induced by the high temperature airflow.
The rotating blades include hollow airfoils that are supplied cooling air through cooling channels. The airfoils include a cooling cavity bounded by sidewalls that define the cooling cavity. The cooling cavity is partitioned into cooling chambers that define flow paths for directing the cooling air.
During rotor blade manufacture, openings are formed along the airfoil for discharging cooling air from the airfoil cavity. More specifically, an electric discharge machining (EDM) process is used to extend the openings from the airfoil trailing edge into the airfoil cavity. At least some known EDM fixtures are used to machine turbine blade assemblies. Because of a curvature of the airfoil, accurately forming the openings in the airfoil may be a time consuming and difficult task. To facilitate improving the EDM process, a clamping apparatus is used to secure the blade assembly. At least some known clamping assemblies are complex and expensive. Consistent, repeatable locating and securing of blade assemblies facilitates precision machining.